JPH07211456A - Method for sealing organic EL element - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a method for sealing an organic EL element, which can prevent oxygen and water from being mixed into a liquid sealing material and can prolong the life of the organic EL element. [Structure] A transparent container 2 containing an element 10 and a container 4 containing a sealing material 3 are arranged in a vacuum deaeration tank 1, and then,
The transparent container 2 under high vacuum by degassing is dipped in the sealing material 3, then the inert gas 6 is introduced to inject the sealing material 3 into the transparent container 2, and then returned to normal pressure to be transparent. The sealing port 5 of the container 2 is sealed with a sealing material.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an organic EL (electroluminescence).
The present invention relates to an element sealing method. More specifically, the present invention relates to a sealing method that is effective for preserving and prolonging the life of organic EL devices used mainly for various displays and light emitting devices for information industrial equipment.

[0002]

2. Description of the Related Art An organic EL device is constructed by sandwiching an organic light emitting body between opposing electrodes, and electrons are injected from one electrode and holes are injected from the other electrode. Light emission occurs when the injected electrons and holes recombine in the light emitting layer. This organic EL element is expected to be developed as a full-color flat panel display or as an alternative to an LED because of its high impact resistance and high visibility, and the variety of emission colors of organic materials.

In order to store the organic EL element and prolong the life of the element, the organic EL element is put into a transparent glass container and sealed with a liquid sealing material. For example, using liquid fluorinated carbon as the sealing material,
As a method of immersing the element in the liquid fluorinated carbon compound, for example, (1) liquid fluorinated carbon is put in a transparent glass container, an EL element with an electrode terminal is put therein, an electrode is pulled out, and a lid is put on. (2) At least one side of the EL element with electrode terminals is covered with a transparent plastic sheet, and both sides are sealed in a bag shape so that the electrode terminals come out of the plastic. Method of sealing the injection port after injection, (3) Arrangement of the box with one side open with the injection port so that the electrode terminal goes out to the side of the EL element with electrode terminal that does not extract light A method is known in which the liquid fluorinated carbon is injected through the injection port and then the injection port is sealed (JP-A-5-41281).
Issue).

[0004]

However, in such a method, since the liquid sealing material is injected in the air, it is difficult to completely prevent the mixing of oxygen and water in the air into the liquid sealing material. Met. Therefore, the cathode material and the organic material are deteriorated, which is not sufficient for the preservation of the device and the prolongation of the device life. The present invention has been made in view of the above problems, and it is possible to prevent mixing of oxygen and water into a liquid encapsulating material and to prolong the life of the organic EL element. The purpose is to provide a stopping method.

[0005]

In order to achieve the above object, according to the present invention, a method for sealing an organic EL element, which comprises injecting a liquid sealing material into a transparent container containing an organic EL element, comprising: a) A step of separately arranging a transparent container having an inlet and a liquid sealing material, in which an organic EL element is loaded, in a vacuum deaeration tank, and b) deaeration of the vacuum deaeration tank A high vacuum of 10 ^-1 Pa to 10 ^-6 Pa and then immersing the sealing port of the transparent container in the sealing material solution, c).
A step of introducing an inert gas containing no water into the vacuum degassing tank and injecting the liquid sealing material into the transparent container by a pressure difference, d) returning the vacuum degassing tank to normal pressure, and There is provided a method for sealing an organic EL element, which includes the step of taking out from a vacuum deaeration tank and then sealing the sealing port with a sealing material. Further, there is provided a method for sealing an organic EL element, wherein the liquid sealing material is liquid fluorinated carbon. Further, there is provided a method for sealing an organic EL element, wherein the water-free inert gas is nitrogen gas (N ₂ ), argon gas (Ar) or helium gas (He).

The structure of the organic EL element used in the present invention will be described below. The structure of the element used in the present invention is not particularly limited, and any structure can be adopted. Examples include anode / light emitting layer / cathode, anode / hole injection layer / light emitting layer / cathode, anode / light emitting layer / electron injection layer / cathode, or anode / hole injection layer / light emitting layer / electron injection layer / cathode. be able to. Further, each layer may be a laminate of a plurality of layers or a mixed layer of a plurality of materials. Each of these organic layers is heated, for example, in a container containing the organic material proposed in Japanese Patent Application No. 5-028659 to evaporate the organic material from the container and deposit the evaporated organic material on one electrode. Then, it can be formed by a method of forming an organic material layer. The thickness of each layer is not particularly limited. The thickness of each layer excluding the Yin and Yang electrodes is usually 5 nm to 5 μ.
m. The material is not particularly limited as long as it is usually used for an organic EL element. Hereinafter, each component of the organic EL device including the anode / hole injecting / transporting layer / light emitting layer / electron injecting / transporting layer / cathode will be specifically described.

Supporting Substrate The organic EL device used in the present invention is preferably formed on a supporting substrate. The supporting substrate used is preferably transparent, and specific examples thereof include glass, transparent plastic, and quartz.

Anode As the anode in the organic EL device used in the present invention, a metal, an alloy, an electrically conductive compound having a large work function (4 eV or more), and a mixture thereof as an electrode substance can be preferably used. . Specific examples of such an electrode material include metals such as Au, CuI, ITO and SnO.
₂ , a transparent material or a semitransparent material having a dielectric property such as ZnO can be mentioned. The anode can be formed by forming a thin film of these polar materials by a method such as vapor deposition or sputtering. When light emission is taken out from this electrode, it is desirable that the transmittance be greater than 10%, and that the sheet resistance of the electrode be several hundred Ω / □ or less. The film thickness depends on the material, but is usually 10 nm to 1 μm, preferably 10 nm to 1 μm.
It can be selected in the range of 200 nm.

On the other hand, the cathode has a small work function (4 eV or less).
A metal, an alloy, an electrically conductive compound, or a mixture thereof can be used as an electrode material. Specific examples of such an electrode material include sodium, sodium-potassium alloy, magnesium, lithium, magnesium /
Copper mixtures, Al / (Al ₂ O ₃ ), indium, rare earth metals and the like can be mentioned. The cathode can be prepared by forming a thin film of these electrode substances by a method such as vapor deposition or sputtering. Further, the sheet resistance as an electrode is preferably several hundred Ω / □ or less, and the film thickness can be selected in the range of usually 10 nm to 1 μm, preferably 50 to 200 nm. In addition,
In this EL element, it is preferable that either the anode or the cathode is transparent or semi-transparent, because the electrode itself transmits the emitted light and the emission efficiency of the emitted light is improved.

Light-Emitting Layer The organic compound that can be used as the material for the light-emitting layer is not particularly limited, but is a fluorescent brightening agent such as benzothiazole-based, benzimidazole-based, or benzoxazole-based, a metal chelated oxinoid compound, and styrylbenzene. Examples thereof include system compounds.

Specific examples of the compound name include those disclosed in JP-A-59-194393. Typical examples thereof include 2,5-bis (5,7-di-t-pentyl-2-benzoxazolyl) -1,3,4-thiadiazole and 4,4′-bis (5,7-t- Pentyl-2-benzoxazolyl) stilbene, 4,4′-bis [5,7-di- (2-methyl-2-butyl) -2-benzoxazolyl] stilbene, 2,5-bis (5 , 7-Di-t-pentyl-2-benzoxazolyl) thiophene, 2,5-bis [5-
α, α-Dimethylbenzyl-2-benzoxazolyl]
Thiophene, 2,5-bis [5,7-di- (2-methyl-2-butyl) -2-benzoxazolyl] -3,4 diphenylthiophene, 2,5-bis (5-methyl-2)
-Benzoxazolyl) thiophene, 4,4'-bis (2-benzoxazolyl) biphenyl, 5-methyl-
2- [2- [4- (5-methyl-2-benzoxazolyl) phenyl] vinyl] benzoxazole, 2- [2
-(4-Chlorophenyl) vinyl] naphtho [1,2-
d] Benzoxazoles such as oxazole, 2-2 ′
Benzothiazoles such as-(p-phenylenedivinylene) -bisbenzothiazole, 2- [2- [4- (2-benzimidazolyl) phenyl] vinyl] benzimidazole, 2- [2- (4-carboxyphenyl) vinyl ]
Fluorescent brighteners such as benzimidazole series such as benzimidazole can be mentioned. In addition, other useful compounds are Chemistry of Synthetic Soybean 1
971, 628-637 and 640.

As the chelated oxinoid compound, for example, those disclosed in JP-A-63-295695 can be used. Typical examples thereof are tris (8-quinolinol) aluminum, bis (8-quinolinol) magnesium, bis (benzo [f] -8-quinolinol) zinc, bis (2-methyl-).
8-quinolinolate) aluminum oxide, tris (8-quinolinol) indium, tris (5-methyl-8-quinolinol) aluminum, 8-quinolinol lithium, tris (5-chloro-8-quinolinol) gallium, bis (5- Chloro-8-quinolinol) calcium, poly [zinc (II) -bis (8-hydroxy-5-)
8-hydroxyquinoline-based metal complex such as quinolinonyl) methane] and dilithium epinetridione.

As the styrylbenzene compound, for example, those disclosed in European Patent No. 0319881 and European Patent No. 0373582 can be used. As typical examples thereof, 1,4-bis (2-methylstyryl) benzene and 1,4-bis (3
-Methylstyryl) benzene, 1,4-bis (4-methylstyryl) benzene, distyrylbenzene, 1,4-
Bis (2-ethylstyryl) benzene, 1,4-bis (3-ethylstyryl) benzene, 1,4-bis (2-
Methylstyryl) -2-methylbenzene, 1,4-bis (2-methylstyryl) -2-ethylbenzene and the like can be mentioned.

The distyrylpyrazine derivative disclosed in JP-A-2-252793 can also be used as a material for the light emitting layer. Typical examples are 2,
5-bis (4-methylstyryl) pyrazine, 2,5-bis (4-ethylstyryl) pyrazine, 2,5-bis [2
-(1-naphthyl)) vinyl] pyrazine, 2,5-bis (4-methoxystyryl) pyrazine, 2,5-bis [2
Examples thereof include-(4-biphenyl) vinyl] pyrazine and 2,5-bis [2- (1-pyrenyl) vinyl] pyrazine. Others, such as European Patent No. 0
The polyphenyl compound disclosed in the specification of 387715 can also be used as a material for the light emitting layer.

Further, in addition to the above-mentioned optical brightener, metal chelated oxinoid compound, styrylbenzene compound, etc., for example, 12-phthaloperinone (J. Appl.
Phys., 27, L713 (1988)), 1, 4
-Diphenyl-1,3-butadiene, 1,1,4,4-
Tetraphenyl-1,3 butadiene (above Appl. Phys.
Lett., Vol. 56, L799 (1990)), naphthalimide derivative (JP-A-2-305886), perylene derivative (JP-A-2-189890), oxadiazole derivative (JP-A-2-216791). Publication, or the oxadiazole derivative disclosed by Hamada et al. At the 38th Joint Lecture on Applied Physics), aldazine derivative (JP-A-2-220393), pyrazirine derivative (JP-A-2-220394), Cyclopentadiene derivative (JP-A-2-289675), pyrrolopyrrole derivative (JP-A-2-296891),
Styrylamine derivatives (Appl. Phys. Lett., Volume 56,
L799 (1990)), coumarin-based compounds (Japanese Patent Laid-Open No. 2-191694), International Publication WO90 / 1.
3148 and Appl. Phys. Lett., Vol 58, 18, P1982 (1991)
The polymer compounds and the like as described in 1) can also be used as the material of the light emitting layer.

In the present invention, an aromatic dimethylidyne compound (European Patent No. 0388876) is used as a material for the light emitting layer.
No. 8 and those disclosed in JP-A-3-231970) are preferably used. As a specific example, 1,4
-Phenylenedimethyridin, 4,4-Phenylenedimethylidene, 2,5-Xylylenedimethylidene, 2,6
-Naphthylene dimethylidene, 1,4-biphenylene dimethylidene, 1,4-p-terephenylene dimethylidene, 9,10-anthracene diyl dimethylidene, 4,4'-bis (2,2- Mention may be made of di-t-butylphenylvinyl) biphenyl, 4,4′-bis (2,2-diphenylvinyl) biphenyl and the like, and derivatives thereof.

The thickness of the light emitting layer thus formed is not particularly limited and may be appropriately selected depending on the circumstances, but is usually preferably in the range of 5 nm to 5 μm.
The light emitting layer in the organic EL device has an injection function capable of injecting holes from the anode or the hole injection layer and electrons from the cathode or the electron injection layer when an electric field is applied, and the injected charge ( It provides a transport function to move (electrons and holes) by the force of the electric field, a field for recombination of electrons and holes,
It has a light-emitting function that connects this to light emission. In addition,
There may be a difference between the ease with which holes are injected and the ease with which electrons are injected. The transport function represented by the mobilities of holes and electrons may have different sizes, but it is preferable to move at least one of them.

Hole Injecting Layer As a material of the hole injecting layer provided as necessary, those conventionally used as a hole injecting material of a photoconductive material and a hole injecting layer of an organic EL element are used. Any known one can be selected and used. The material of the hole injection layer has either hole injection or electron barrier properties, and may be either an organic substance or an inorganic substance.

Specific examples include, for example, triazole derivatives (see US Pat. No. 3,112,197) and oxadiazole derivatives (US Pat.
189,447, etc.), imidazole derivatives (see Japanese Examined Patent Publication No. 37-16096, etc.), polyarylalkane derivatives (US Pat. Nos. 3,615,402 and 3,820,989). , Ibid. 3,54
2,544, Japanese Patent Publication No. 45-555, 5
1-10983, JP-A-51-93224, JP-A-55-17105, JP-A-56-4148, JP-A-55-108667, and JP-A-55-15695.
No. 3, JP-A-56-36656, etc.), pyrazoline derivatives and pyrazolone derivatives (US Pat. No. 3,1).
No. 80,729, No. 4,278,746, JP-A No. 55-88064, and No. 55-8806.
5 gazette, the same 49-105537 gazette, the same 55-51.
086, 56-80051, 56-8
No. 8141, No. 57-45545, No. 54-
No. 112637, No. 55-74546, etc.), a phenylenediamine derivative (US Pat. No. 3,61).
5,404, Japanese Patent Publication No. 51-10105,
46-3712 and 47-25336,
JP-A-54-53435 and JP-A-54-110536.
JP-A No. 54-119925, etc.), arylamine derivatives (US Pat. Nos. 3,567,450, 3,180,703, and 3,24).
No. 0,597, No. 3,658,520, No. 4,232,103, No. 4,17.
5,961, No. 4,012,376, Japanese Patent Publication No. Sho 49-35702, No. 39-2757.
No. 7, JP-A-55-144250, and No. 56-
No. 119132, No. 56-22437, West German Patent No. 1,110,518, etc.), amino-substituted chalcone derivatives (see US Pat. No. 3,526,501, etc.), oxazole derivatives (US). Patent No. 3,2
No. 57,203), styrylanthracene derivatives (see JP-A-56-46234, etc.), fluorenone derivatives (JP-A-54-110837).
Hydrazone derivatives (U.S. Pat. No. 3,7,7).
17,462, JP-A-54-59143, JP-A-55-52063, JP-A-55-52064, JP-A-55-46760, and JP-A-55-85495.
No. 57-11350, No. 57-1487.
49, JP-A-2-311591, etc.),
Stilbene derivative (JP-A-61-1210363,
No. 61-228451, No. 61-14642, No. 61-72255, No. 62-47646, No. 62-36674, No. 62-10652.
No. 62-30255, No. 60-9344.
5, gazette 60-94462, gazette 60-174.
749, 60-175052, etc.),
Silazane derivatives (U.S. Pat. No. 4,950,950), polysilane-based (JP-A-2-204996), aniline-based copolymers (JP-A-2-28263), JP-A-1121399. The conductive polymer oligomers (particularly thiophene oligomers) disclosed in (1) can be mentioned.

The above materials can be used as the material for the hole injecting layer.
No. 3,295,965), aromatic tertiary amine compounds and styrylamine compounds (US Pat. No. 4,127,412, JP-A-53-270).
No. 33, No. 54-58445, No. 54-14
No. 9634, No. 54-64299, No. 55-
79450, 55-144250, and 5
6-119132, 61-295558, 61-98353, 63-295695.
It is preferable to use aromatic tertiary amine compounds.

Typical examples of the porphyrin compound are porphine, 1,10,15,20-tetraphenyl-21H, 23H-porphine copper (II), 1,10,
15,20-Tetraphenyl-21H, 23H-porphine zinc (II), 5,10,15,20-tetrakis (pentafluorophenyl) -21H, 23H-porphine, silicon phthalocyanine oxide, aluminum phthalocyanine chloride, phthalocyanine (metal-free ),
Examples thereof include dilithium phthalocyanine, copper tetramethylphthalocyanine, copper phthalocyanine, chromium phthalocyanine, zinc phthalocyanine, lead phthalocyanine, titanium phthalocyanine oxide, Mg phthalocyanine and copper octamethylphthalocyanine.

Representative examples of the aromatic tertiary amine compound and styrylamine compound include N, N,
N ', N'-tetraphenyl-4,4'-diaminophenyl, N, N'-diphenyl-N, N'-bis- (3-
Methylphenyl)-[1,1'-biphenyl] -4,
4'-diamine, 2,2-bis (4-di-p-tolylaminophenyl) propane, 1,1-bis (4-di-p-
Tolylaminophenyl) cyclohexane, N, N,
N ', N'-tetra-p-tolyl-4,4'-diaminophenyl, 1,1-bis (4-di-p-tolylaminophenyl) -4-phenylcyclohexane, bis (4-dimethylamino-2) -Methylphenyl) phenylmethane,
Bis (4-di-p-tolylaminophenyl) phenylmethane, N, N'-diphenyl-N, N'-di (4-methoxyphenyl) -4,4'-diaminobiphenyl, N,
N, N ', N'-tetraphenyl-4,4'-diaminophenyl ether, 4,4'-bis (diphenylamino) quadriphenyl, N, N, N-tri (p-tolyl) amine, 4- (Di-p-tolylamino) -4'-
[4 (di-p-tolylamino) styryl] stilbene,
4-N, N-diphenylamino- (2-diphenylvinyl) benzene, 3-methoxy-4'-N, N-diphenylaminostilbenzene, N-phenylcarbazole and the like can be mentioned. Further, the above-mentioned aromatic dimethylidyne compound shown as the material for the light emitting layer can also be used as the material for the hole injection layer.

The thickness of the hole injection layer is not particularly limited, but is usually 5 nm to 5 μm. The hole injection layer may have a single-layer structure composed of one or more of the above-mentioned materials, or a multi-layer structure composed of a plurality of layers having the same composition or different compositions.

Electron Injection Layer The electron injection layer, which is provided if necessary, may have a function of transmitting the electrons injected from the cathode to the light emitting layer,
As the material, any one of conventionally known compounds can be selected and used.

Specific examples include nitro-substituted fluorenone derivatives, JP-A-57-149259 and JP-A-58-5.
5450, 63-104061 and the like, anthraquinodimethane derivatives disclosed in Polymer Prep
rints, Japan Vol.37, No. 3 (1988) p.681 etc., diphenylquinone derivative, thiopyran dioxide derivative, heterocyclic tetracarboxylic acid anhydride such as naphthaleneperylene, carbodiimide, Japanese Journal of Applied
Physics, 27, L 269 (1988), JP-A-60-69657, JP-A-61-143764, and JP-A-61-114815.
Fluorenylidene methane derivatives disclosed in, for example, JP-A Nos. 61-225151 and 61-23.
Anthraquinodimethane derivatives and anthrone derivatives disclosed in Japanese Patent No. 3750, Appl. Phys. Lett.,
55,15,1489 and oxadiazole derivatives disclosed by Hamada et al. At the 38th Joint Lecture Meeting on Applied Physics,
A series of electron-transporting compounds disclosed in JP-A-59-194393 can be mentioned. Incidentally, JP-A-59
Although the electron-transporting compound is disclosed as a material for the light-emitting layer in Japanese Patent Laid-Open No. 194393, it has been clarified by the present inventors that it can be used as a material for the electron-injecting layer.

A metal complex of an 8-quinolinol derivative, specifically tris (8-quinolinol) aluminum, tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8). -Quinolinol) aluminum, tris (2-methyl-8-quinolinol)
Aluminium, etc., and the central metal of these metal complexes are I
A metal complex that replaces n, Mg, Cu, Ca, Sn, or Pb can also be used as a material for the electron injection layer. In addition, metal-free or metal phthalocyanine or those whose terminal is substituted with an alkyl group, a sulfone group or the like is also desirable. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as the material of the electron injection layer.

The thickness of the electron injection layer is not particularly limited, but is usually 5 nm to 5 μm. The electron injection layer may have a single-layer structure composed of one or more of the above-mentioned materials, or a multi-layer structure composed of a plurality of layers having the same composition or different compositions.

Next, the method for sealing the organic EL element of the present invention will be specifically described with reference to the drawings. FIG. 1 is an explanatory view schematically showing each step of a specific example of the method for sealing an organic EL element of the present invention. Hereinafter, each step will be described in order. 1. A step of separately disposing a transparent container having an encapsulation port, in which an organic EL element is loaded, and a container in which a liquid sealing material is placed, in a vacuum deaeration tank (FIG. 1 (a)).

Examples of the vacuum degassing tank 1 used in the present invention include a tank having a degassing mechanism using a vacuum pump.

Further, the transparent container 2 used in the present invention is not particularly limited as long as it is a transparent container into which an organic EL element can be loaded with an electrode outlet, and examples thereof include glass, quartz and metal. Can be mentioned.
Among them, glass is preferable because it has low moisture permeability.
Particularly, a film having a film thickness of 1 mm or more is preferable. The shape of the container is, for example, as shown in FIG. 2, a glass substrate 21 as a supporting substrate and an organic EL element 1 formed thereon.
And a glass case 24 that covers 0, and a part of the glass case 24 is provided with the sealing port 5. The shape of the sealing port is not particularly limited, and examples thereof include those having the cross section of FIG. In this example, the organic EL element 10 is the anode 2
The organic layer 20 is sandwiched between the cathode 2 and the cathode 23. The glass case 24 includes an anode 22 and a cathode 23.
And the adhesive portion 25.

Examples of the liquid encapsulating material used in the present invention include fluorinated carbon, liquid polybutene, liquid polypropylene and liquid polyethylene. Of these, fluorinated carbon having a water solubility of 10 ppm or less is preferable. As a specific product name, "Fluorinert" manufactured by Sumitomo 3M Ltd. can be mentioned. However, the maximum dissolved amount of air and oxygen in 100 ml is 20 to 40 ml for air and 30 to 60 for oxygen.
Deoxygenation (eg bubbling with an inert gas) is required to reach ml. In the present invention, since the liquid encapsulating material is injected under high vacuum, it is possible to prevent air (oxygen) and moisture from being mixed. As a specific arrangement method, a container 4 containing a liquid sealing material 3 is arranged below the vacuum degassing tank 1, and a transparent container 2 containing an organic EL element is provided above the container 4 with its sealing port. It is preferable to arrange so that 5 is opposed to the liquid sealing material 3. Specifically, for example, the sealing port 5 is arranged so that the sealing port 5 is located several mm to several cm above the liquid surface of the liquid sealing material 3.

2. Degas the vacuum degassing tank to 10 ^-1 Pa to ¹
The process of evacuating the tank by evacuating the tank to a high vacuum of 0 ^-6 Pa and then immersing the sealing port of the transparent container in the sealing material solution (Fig. 1 (b)) is, for example, evacuation with a rotary pump or a diffusion pump. Can be mentioned. The resulting high vacuum is
The pressure is set to 10 ^-1 Pa to 10 ^-6 Pa. If it is larger than 10 ^-1 Pa, oxygen and humidity are easily mixed, and if it is smaller than 10 ^-6 Pa, it is difficult to reach it. 10 ⁻³ to 10 ⁻⁵ Pa is preferable. The immersion of the sealing port 5 of the transparent container 2 in the liquid sealing material 3 is such that the sealing port 5 is entirely below the liquid surface of the liquid sealing material 3.

3. A step of introducing an inert gas containing no water into the vacuum degassing tank and injecting the liquid sealing material into the transparent container by a pressure difference (FIG. 1 (c)). Examples of the kind include nitrogen (N ₂ ), argon (Ar), helium (He), neon (Ne) and the like. This inert gas must contain no water (for example, 100 ppm or less),
It is preferable to ensure the absence of water by passing liquid nitrogen. The method of introducing the inert gas into the vacuum degassing tank 1 is, for example, to be performed gradually through a leak valve. Further, the liquid sealing material 3 is injected into the transparent container 2 by utilizing the pressure difference, and the pressure difference is 1 Pa to 10 ^-2 Pa depending on the viscosity of the liquid sealing material 3 and the like. Is preferred. If it is larger than 1 Pa, it needs to be processed, and 10
^{If it is} less than ^-2 Pa, it takes a long time for injection.

4. Returning the vacuum deaeration tank to normal pressure, taking out the transparent container from the vacuum deaeration tank, and then sealing the sealing port with a sealing material (Fig. 1 (d)) To return the vacuum deaeration tank 1 to normal pressure For example, the vacuum degassing tank may be opened.

The sealing material used in the present invention is not particularly limited, and sealing materials made of various organic polymers can be used. For example, a photocurable resin can be mentioned, and among them, a resin having low moisture permeability is preferable. Specifically, a resin having a moisture permeability of 0.1% or less can be used. As another sealing method, there may be mentioned a method of covering the sealing port 5 with a fluorine-based resin processed into a lid shape and heating and pressing with a hot-melt resin to fix the sealing.

[0036]

EXAMPLES The present invention will be described in more detail below with reference to examples. Example 1 A white glass substrate on which ITO, which is a transparent electrode having a film thickness of 100 nm, was formed, was ultrasonically cleaned with isopropyl alcohol for 10 minutes. Further, after spray-drying with dry He, it is further washed with a UV / ozone cleaning device (UV300 made by Samco International) for 30 minutes and attached to a substrate holder of a commercially available vacuum deposition device (made by Nippon Vacuum Co., Ltd.). It was In the resistance heating boat (made of tungsten) of this vacuum vapor deposition apparatus, the T
Alq shown below, which is a luminescent material in a boat other than PD
(Tris (8-quinolinol) aluminum) for each 20
0 mg each was added.

[0037]

[Chemical 1]

[0038]

[Chemical 2]

The vacuum degassing tank of the vacuum vapor deposition apparatus was evacuated to 10 ^-4 Pa, and the boat containing TPD was heated to TP.
The D layer was formed with a film thickness of 60 nm. Further, the boat containing Alq was heated to form an Alq layer with a film thickness of 60 nm.
Next, the vacuum deaeration tank was returned to the atmosphere, a vapor deposition mask was attached on the substrate, and further exhausted to 10 ⁻⁴ Pa. At this time, a magnesium ribbon was placed in the resistance heating boat and silver was placed in another resistance heating filament. Heat the boat containing magnesium and the filament containing silver at the same time,
Simultaneous vapor deposition was performed so that the atomic ratio of magnesium to silver was about 10: 1. The thickness of the magnesium: silver layer was set to 200 nm, and the cathode formation was completed. Through the above steps, the production of the organic EL element was completed.

Next, the device was taken out in the atmosphere and a glass case was bonded to the lower substrate so as to cover the entire device. Adhesive is a photocurable resin made by Sumitomo 3M Ltd., product name 3
042B was used for adhesion under irradiation of ultraviolet rays. A 1.5 mφ hole is previously formed in this case as an inlet for the sealing material. This was placed in a vacuum degassing tank. As the sealing material, Fluorinert FC70 (trade name, manufactured by Sumitomo 3M Ltd., kinematic viscosity at 25 ° C., 13.4 cSt) was used. Fluorinert FC70 is fully deoxidized beforehand,
The deaerated product was placed in a vacuum deaeration tank and allowed to stand for 100 hours. The arrangement is such that a container containing Fluorinert FC70 as a liquid sealing material is arranged below the vacuum deaeration tank, and a glass case as a transparent container having an organic EL element is placed above the container. The enclosing ports were arranged so as to face each other at a position 1 cm above the liquid surface of the sealing material. Next, using a rotary pump, the vacuum deaeration tank was evacuated to a high vacuum of 10 ⁻⁴ Pa. Next, all of the glass case inlets are Fluorinert FC7
The glass case was immersed so as to be below the liquid level of 0. Next, nitrogen gas containing no water is introduced into the vacuum degassing tank through a leak valve, and the pressure difference is used to fluorinate F.
C70 was poured into a glass case. The pressure difference in this case was about 10 ^-1 Pa. Next, the vacuum deaeration tank is opened to return it to normal pressure, and the glass case in which the organic EL element is loaded is taken out from the vacuum deaeration tank.
% Of the photo-curable resin to seal the sealing port.

Life Test A DC voltage was applied to the element sealed in Example 1 to set the initial luminance to 500 cd / m ² . When driven at a constant current in air, the half life was 3000 hours. This 3000
The non-light emitting area (dark spot) after the lapse of time was not observed with the naked eye.

Comparative Example 1 Except that the sealing material was injected in air instead of vacuum injection,
An element was prepared and sealed in the same manner as in Example 1. When tested under the same conditions as in Example 1, dark spots were found to grow after the initial 100 hours. The size of the duck spot was about 50 to 100 μmφ, and its presence could be detected with the naked eye. The half-life of this device was 2500 hours, but at this point the size of the dark spots had increased and had grown to nearly 200 μm.

Comparative Example 2 Sumitomo 3M Co., Ltd. used in Example 1 as a sealing material,
An element was prepared and sealed in the same manner as in Example 1 except that silicone oil (YF33 manufactured by Toshiba Silicone Co., Ltd.) was vacuum-injected in place of the product name Fluorinert FC70. Next, when the test was performed under the same conditions as in Example 1, when the time exceeded 200 hours, peeling of the cathode occurred and the place became a non-light emitting region. Therefore, it was found that silicone oil cannot be used because it causes peeling of the cathode.

Comparative Example 3 Silicone oil (TSF451 manufactured by Toshiba Silicone Co., Ltd., viscosity: 10) was used instead of the one used in Example 1 as the sealing material.
A device was prepared and sealed in the same manner as in Example 1 except that 0 cSt) was used. The test was then carried out under the same conditions as in Example 1. As a result, similar peeling occurs,
It turns out that it cannot be used.

Comparative Example 4 Instead of the sealing material used in Example 1, fluorine-modified silicone oil (trade name: FL100, manufactured by Shin-Etsu Silicone Co., Ltd., polysiloxane terminal trifluoromethylated) was used. An element was prepared and sealed in the same manner as in Example 1 except that. As a result, the degree of exfoliation of the cathode was reduced, but it was also found that a non-light emitting region was generated and the cathode could not be used. From the above test results,
It has been found that silicone oil cannot be used because it peels off the cathode, and fluorination is a method of improving, and it is most preferable to use completely fluorinated hydrocarbon.

[0046]

As described above, the organic EL device of the present invention
To obtain a long-life organic EL device without emission defects by preventing air (oxygen) and water from being mixed into a liquid encapsulating material and suppressing the growth of dark spots by a device sealing method. You can

[Brief description of drawings]

FIG. 1 is an explanatory view schematically showing each step of a specific example of a method for sealing an organic EL element of the present invention.

FIG. 2 is a cross-sectional view schematically showing an example of the shape of a transparent container used in the present invention.

[Explanation of symbols]

 1 Vacuum Deaeration Tank 2 Transparent Container 3 Liquid Encapsulating Material 4 Container for Liquid Encapsulating Material 5 Sealing Port 6 Inert Gas 10 Organic EL Element 20 Organic Layer 21 Glass Substrate 22 Anode 23 Cathode 24 Glass Case 25 Adhesive Part

Claims (3)

[Claims] 1. A method for sealing an organic EL element, which comprises injecting a liquid sealing material into a transparent container containing the organic EL element, comprising: a) placing the organic EL element in a vacuum deaeration tank; A step of separately disposing a transparent container having a sealing port and a container containing a liquid sealing material, b) deaeration of a vacuum deaeration tank to a high vacuum of 10 ^-1 Pa to 10 ^-6 Pa, and then , A step of immersing the sealing port of the transparent container in the sealing material solution, c) introducing an inert gas containing no water into the vacuum degassing tank, and applying a liquid sealing material into the transparent container by a pressure difference. Injecting step, d) Returning the vacuum deaeration tank to normal pressure, taking out the transparent container from the vacuum deaeration tank, and then sealing the sealing port with a sealing material. Method. 2. The method for sealing an organic EL element, wherein the liquid sealing material is liquid fluorinated carbon. 3. A method for sealing an organic EL element, wherein the water-free inert gas is nitrogen gas (N ₂ ), argon gas (Ar) or helium gas (He).